Analog VU Meter Circuit using transistors

The Analog vu meter circuit that works with the integrated amplifier circuit.The signal will sound, the audio amplifier circuit into VU meter circuit.And will show the level of the signal by flashing light. Rhythm of the music with LED.
When entering the power supply to circuit.The input VU meter is connected to the output of the amplifier.When one passes audio input diodes D1, D2, D3 and D4.This serves to divide the audio signal to gradually decrease, respectively.To forward to the individual transistors Q1-Q4.The strength of the incoming signal.Then the voice over R5-R8 limited bias current to flow from Q1-Q4 extend the pin C. To go to drive LED1-LED4 the timing light. And strength of the signal.The LED1 displays audio level light most.and LED4 shows the level signals, the most.

Note: likewise you can see second circuit below that too LEDs.

Simple LED VU meter circuit using transistors

Simple LED VU meter circuit using transistors

25 LEDs VU meter Circuits (Increase LED)

The circuit will increase the input signal to a voltage signal circuits as much as two times.To affect the audio signal into more valuable.This makes all the transistor amplifier to drive LED is very.And emit light much more.

-When raising the power circuit.And the input signal to act through the VR1 to adjust the sound more or less.Then passed to the C1 signal coupling.Then the signal goes into the circuit to add voltage,by the D1 and D2. So D1 and D2, which will make Direct Contact Fire signal into a DC voltage and power split and split positively delete files together.Then filtered to smooth power with C2.The first part of the signal will result to the Q1 R1 bias current expansion work to drive LED1-LED5 to light.The remaining signal is sent through diodes D3, D4 and D5.This will serve to break the sound signal to gradually decrease, respectively. To forward to the transistors Q2-Q4, each level of the signal strength coming.Then expand to the LED current to light the rhythm music.

 25 LEDs Analog VU Meter Circuit using transistors

To add LEDs for 25 LEDs Analog VU Meter Circuit using transistors

If you want to see image vu meter circuit. Please read below.
Analog vu meter
Sound level meter
Let’s to build many VU Meter circuits with LM3914 The complete circuit for VU-meter.

Note: This circuit worked well as Video below:


  1. Rosslie Mohd Sake December 10, 2012 Reply
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